Apparatus for twisting yarn



A g 13, 1968 F. SCRAGG ETAL 3,396,523

APPARATUS FOR TWISTING YARN 2 Sheets-Sheet 1 Filed Feb. 25. 1966 f7 Glir 1968 F. SCRAGG ETAL 3,396,523

APPARATUS FOR TWISTING YARN Filed Feb. 25. 1966 2 Sheets-Sheet 2 United States Patent Olhce 3,396,523 Patented Aug. 13, 1968 3,396,523 APPARATUS FOR TWISTING YARN Frederick Scragg, Trinity, Jersey, Channel Islands, and Walter Parker, Wilmslow, England, assignors to Ernest Scragg & Sons Limited, Cheshire, England, a British company Filed Feb. 25, 1966, Ser. No. 534,279 Claims priority, applicationl/rggt Britain, Feb. 27, 1965,

37 Claims. (Cl. 5734) ABSTRACT OF THE DISCLOSURE A yarn processing apparatus in which twist means located along a path along which a yarn is advanced in one direction twists the yarn, in which twist stopper means are provided upstream of the twist means for preventing a twist produced in the yarn to pass to the upstream side of the twist stopper means, and in which the twist stopper means includes a pair of opposed wall portions between which the yarn passes to the twisting means and which are spaced apart a distance such that yarn passing therebetween contacts the opposed wall portions and is thereby constrained against twisting.

This invention relates to apparatus for twisting yarn and is particularly concerned with twist stopper means for determining the extent of the yarn twisting zone of such apparatus.

In the performance of their function of preventing the propagation of twist beyond a certain point along a running yarn, most twist stoppers depend, for their operation, on the fact that highly twisted yarn has a diameter which is greater than that of the same yarn in the untwisted or lightly twisted state.

It is common practice, in yarn false twist crimping apparatus, to provide upstream of the heater of the apparatus, nip rolls which serve, inter alia, to withdraw yarn from a yarn supply and to prevent the propagation of twist to yarn in transit upstream of the nip of the rolls.

The provision of nip rolls capable of performing both of the aforestated functions satisfactorily over extended period of time presents certain problems; the requirements that the nip rolls shall function satisfactorily to withdraw yarn and to stop twist are to some extent, antagonistic.

On the one hand, in order to perform satisfactorily in withdrawing yarn, there must be good frictional engagement between the rolls and the yarn, and this has led to the practice of cladding one of the rolls with a soft, high friction material, such as polyurethane. On the other hand, in order to ensure satisfactory operation of the nip rolls as a twist stopper it is desirable that the yarn engaging surfaces of both rolls shall be hard. Where one of the rolls has a soft, e.g., polyurethane, yarn engaging surface, yarn which is being rapidly twisted abrades the soft yarn engaging surface of the nip of the rolls with the result that in a relatively short time a circumferential groove is worn into the soft yarn engaging surface.

According to the present invention a yarn processing apparatus comprises: means operative, when yarn is forwarded through the apparatus, to twist the yarn; and a twist stopper having an opening between opposed wall portions of which, in operation, yarn passes to the twisting means, and in which the opposed wall portions are spaced apart by, or are prevented from relative movement which would result in the opposed wall portions being closer together than, a certain distance such that yarn passing between the opposed wall portions is constrained against twisting by the opposed wall portions so that whereas twist is produced by the twisting means in yarn in transit from the twist stopper to the twisting means no twist is produced by the twisting means in yarn in transit upstream of the twist stopper.

The prevention of twist propagation beyond a certain point along the yarn is effected, in such an apparatus, by a device designed specifically to perform this function; since parts of the apparatus disposed upstream of the twist stopper are not instrumental in stopping twist, the design of such parts may be simplified and their operating efficiency improved.

Embodiments of apparatus in accordance with the invention are hereinafter described with reference to the accompanying drawings in which:

FIG. 1 is a schematic diagram of a first yarn false twist apparatus;

FIG. 2 is a schematic diagram of a second yarn false twist apparatus;

FIG. 3 shows, diagrammatically, a first form of twist stopper adapted to be employed in the apparatus of FIGS. 1 or 2;

FIG. 4 shows, diagrammatically, a second form of twist stopper;

FIG. 5 shows, diagrammatically, a perspective view of a preferred form of twist stopper adapted to be employed in the apparatus of FIGS. 1 or 2;

FIG. 6 shows, diagrammatically, a section through the twist stopper of FIG. 5, the section being parallel to the direction of yarn movement through the twist stopper;

FIG. 7 shows diagrammatically a section through a second preferred form of a twist stopper, the section being parallel to the direction of yarn movement through the twist stopper;

FIG. 8 is a diagrammatic perspective view of another form of twist stopper in accordance with the invention;

FIG. 9 is a diagrammatic perspective view of a further form of twist stopper;

FIG. 10 shows, diagrammatically, a section through the twist stopper of FIG. 9, the section being parallel to the direction of yarn movement;

FIG. 11 shows, diagrammatically, a section through yet another twist stopper, the section being parallel to the direction of yarn movement;

FIG. 12 shows a section on the line AA of FIG. 11;

FIG. 13 shows a multi-track yarn contact heater and a plurality of twist stoppers; and

FIG. 14 is a schematic perspective view of an adjustable twist stopper.

The yarn processing apparatus (FIG. 1) comprises yarn false twist means 11 of known construction not forming part of the present invention, a yarn heating zone 13, a yarn cooling zone 15 between the heating zone 13 and the false twist means 11, yarn forwarding means comprising first nip-forming rolls 17 located upstream of the heating zone 13, and second nip-forming rolls 19 located downstream of the false twist means 11, and a twist stopper 21 located downstream of the nip rolls 17 and upstream of the yarn heating zone 13. The yarn heating zone 13 comprises a yarn contact heater.

Yarn Y having a low binding twist of, for example,

half a turn per inch is, in operation of the apparatus (FIG. 1), drawn by the nip rolls 17 from a yarn supply S and is forwarded, by the nip rolls 19, from the nip rolls 17, through the twist stopper 21, the heating zone 13, the cooling zone 15, and the false twist means 11. Crimped yarn issuing from the false twist means is forwarded by the nip rolls 19 to a take-up package T rotated at constant peripheral speed by yarn wind-up means W.

Various modifications of twist stoppers are shown in the FIGS. 3-12 and 14. Common to all twist stoppers shown in the aforementioned figures is an opening 25, respectively 25a25d between opposite wall portions 23, 23, respectively 23a-23d, 23a23d of which the yarn passes to the twisting means 11. The opposed wall portions are spaced apart by a certain distance such that a yarn passing therebetween is constrained against twisting by contact with the opposite wall portions so that whereas the twist produced by the twisting means 11, in yarn in transit between the twist stopper 22 and the false twist means 11, no twist is produced by the twisting means 11 in yarn in transit upstream of the twist stopper.

In the embodiment of the twist stopper shown in FIG. 3 the opening 25 is in form of a narrow channel formed between opposed wall portions 23, 23' of a pair of plates 26 and 26' which may be integrally connected to each other along an edge portion 28 thereof so that the chanellike opening 25 is closed at 28 and open along the edge faces of the plates 26 and 26' opposite the connecting portion 28. The opposed wall portions 23 and 23 are spaced apart about twice the diameter of the individual yarn filaments 27 so as to constrain the filaments to fan out at the entrance end of the opening 25 so that, during their transit through the opening 25, the filaments are side-byside in relationship except where a filament cross-over such as 29, arising as a result of the low binding twist present in the yarn withdrawn from the yarn supply, occurs.

The spacing between the opposed wall portions 23 and 23' need not be so limited; however, the only proviso is that the spacing must not be so large that contact between the yarn and the opposite surface portions is not effective in preventing the propagation of twist to yarn in transit upstream of the twist stopper.

The twist stopper illustrated in FIG. 3 has upstream of the opposed wall portions 23, 23' other wall portions 35 and 35 contiguous with the portions 23, 23', respectively, and inclined with respect thereto and defining a space 37 which tapers toward the opening 25. The provision of the tapering space 37 upstream of the opening 25 minimizes the possibility of damaging the flat yarn by contact with the twist stopper.

The opposed wall portions 23, 23' of the twist stopper of FIG. 3 have hard, smooth and parallel yarn contact surfaces.

The twist stopper illustrated in FIG. 3 is fixedly mounted in any convenient manner by means not shown in the drawing in the region of the downstream end of the heating zone 13 as for instance shown at 21 in FIG. 1 and in a position so that the yarn Y may run in vertical direction through the twist stopper.

The twist stopper yarn in FIG. 4 comprises two plates 40 and 40' preferably releasably connected to each other in any convenient manner by means not shown in FIG. 4. The opening 25a provided in this twist stopper is constituted by a groove for instance formed in the plate 40 of substantially rectangular cross section and the opposite wall portions 23a and 23a of the two plates 40 and 40' which define the opening 25a are again spaced apart in the same manner as described above in connection with FIG. 3. Whereas the plates 26 and 26' of the twist stopper shown in FIG. 3 are substantially plane, the plates 46 and 40' are curved in direction of the passage of the yarn therethrough.

FIGS. and 6 show a further embodiment of a twist stopper according to the present invention. The opening 25b of the twist stopper shown in FIGS. 5 and 6 is defined by the opposed wall portions 23b and 23b of two substantially parallel generally cylindrical rod-like members 43 and 43' which are closest to each other and the spacing between these portions is again the same as mentioned before. In this case the wall portions 35 and 35' of the rods 43 and 43 which are located downstream of the 4 Wall portions 23b and 2317 form a tapering inlet space 37 (FIG. 6) whereas the wall portions 31 and 31' at the upstream side of the closest portions 23b and 235 from a gradually widening outlet space 33. The provision of the tapering space 33 minimizes the possibility of damaging the twisting yarn, and the provision of the tapering space 37 upstream of the opening 25b minimizes the possibility of damaging the flat yarn by contact with the twist stopper. The rod-like members 43 and 43' are respectively supported by backing members 45 and 45'by being connected thereto in any known manner. One of the members, for instance the member 45', has as shown in FIG. 5, at one end thereof a projecting portion 45" abutting against the corresponding face of the blacking member 45 which assures a proper spacing between the rod-like members 43 and 43. The backing members 45 and 45' are preferably releasably connected to each other in any convenient manner, not shown in the drawing, and supported on appropriate support means for instance the supporting frame of the spinning machine, in a manner not shown, so that the yarn may run in substantially vertical direction through the opening 25b.

The members 43 and 43 are composed of hard smooth surface material, such as synthetic sapphire. Where a synthetic sapphire is so employed, the members 43 and 43 may conveniently be made from stock material currently employed in the manufacture of twist trapping pins of yarn false twist spindles.

FIG. 7 shows a further embodiment difiering from the embodiment described in connection with FIGS. 5 and 6 only by the provision of two sets of rod-like members 43 and 43' which are spaced apart from each other in direction of the movement of the yarn. The members of each set are supported spaced apart in direction transverse to the yarn movement by two backing members 46 and 46' which are connected to each other substantially in the same manner as the backing members 45 and 45 of the embodiment shown in FIG. 5.

The twist stopper shown in FIG. 8 comprises two rotary rolls 47 and 47', one of which, for instance the roll 47', may be driven by drive means not shown in the drawing and the other of which, for instance the roll 47, may be driven by frictional contact with the roll 47'. The roll 47 has axially spaced portions 49 and 51 of larger diameter than an intermediate portion 53 and the large diameter portions of the roll 47 contact corresponding large diameter portions 47' and 51' of the roll 49' between which a portion of smaller diameter 53' is located. The small diameter portions 53 and 53' define between diametrically opposite portions 23c and 23c an opening 25c, which lies in the plane containing the axes of the rolls 47 and 47. As with the twist stopper of FIG. 5, the small diameter portions 53 and 53' define upstream and downstream of the opening 250 oppositely directed tapering spaces which communicate with the opening 25.

The roll 47 is preferably supported by carrier means, not shown, movable so as to be displaceable away from the roll 47'.

The roll 47 is biased, for instance by springs not shown in the drawing, toward the roll 47'. Movement of the roll 47 away from the roll 47' facilitates threading yarn between the opposed wall portions of the opening 25. The twist stopper shown in FIG. 8 may be modified by providing on each roll only one portion of enlarged diameter in frictional contact with the enlarged diameter portion of the other roll so that the opening 25 is open toward one end of the rolls. In such an arrangement the rolls 47 and 47' are turnably mounted only at the ends thereof provided with the enlarged diameter portion so that a yarn Y can be threaded from the other ends of the rolls between the opposed wall portions without moving the roll 47 away from the roll 47.

In general, for ease of threading, twist stoppers the opening 25 of which are not bounded on all sides are to be preferred to twist stoppers in which the openings have a closed boundary. For this reason the last mentioned roll type twist stop arrangement is to be preferred to that specifically shown in FIG. 8, and the twist stopper shown in FIG. 3 which has a channel open at one side is to be preferred to the twist stopper shown in FIG. 4, in which the opening 25a is in the form of an aperture.

It is inevitable that the twist stopper shall impose some frictional drag on the yarn Y; all things being equal, however, the drag produced by the twist stoppers as shown in FIGS. 5, 7 or 8 is likely to be appreciably less than the drag imposed by twist stoppers such as those shown in FIG. 3 or 4. Where, as in the roll type twist stopper of FIG. 8, the yarn contact surfaces of the opposed wall portions are not only short but also move with the peripheral speed of the yarn, the frictional drag may be very small indeed.

The twist stoppers shown in FIGS. 9 and 10 or FIG. 11 differ from the other twist stoppers descriped above in that their openings d have a circular cross section and, hence, a very large (theoretically infinite) number of diametrically opposed wall portions 23d and 23d. The diameter of the opening 25d is such that yarn passing therethrough is constrained against twisting by contact with the portions defining the opening so that Whereas twist is produced by the twisting means 11, in yarn in transit between the twist stopper and the false twist means 11, no twist is produced between the twisting means 11 in yarn in transit upstream of the twist stopper. The twist stoppers shown in FIGS. 9 and 11 will temporarily alter the cross sectional area of the yarn passing therethrough without altering its cross sectional shape.

The twist stopper of FIG. 9 comprises a thin plate having a series of circular apertures 25d for accommodating the passage of yarns of different diameter; the twist stopper of FIGS. 11 and 12 comprises a short length of tubing 61, e.g., of the sort used in the manufacture of hypodermic needles. In the twist stopper of FIG. 9 each circular aperture has countersunk end portions 63 and 65 (FIG. 10) which define oppositely directed tapering spaces communicating with the opening 25d; in the twist stopper of FIG. 11 oppositely directed tapering spaces are defined by belled out end portions 67, 69 of the tubing.

Between the extreme case of a twist stopper, e.g., the twist stopper of FIG. 3 having two fiat opposed parallel wall portions spaced apart by about twice the yarn filament diameter, and the other extreme case of a twist stopper as shown, e.g., in FIG. 11, having a large number of diametrically opposed wall portions, it is within the ambit of the invention to provide twist stoppers the openings of which may have, for example, an elliptical or polygonal cross section.

The twist stoppers of FIGS. 3-8 may have a plurality of openings as 25, opposed wall portions of which are spaced apart by different amounts, the plurality of openings accommodating yarns having different diameters. The openings may be laterally adjacent portions of a passage through the twist stopper.

For example, one of the opposed wall portions of the channel-shaped opening of FIG. 3 may have laterally adjacent step portions which define with the opposed wall portion 23' a plurality of laterally adjacent openings which prevent the propagation of twist to yarn in transit upstream of the twist stopper, for different diameter yarns.

The twist stoppers of FIGS. 3-7 may, where the twist stopper is in the form of an assembly, have calibrated adjustment means. Such an arrangement is for instance schematically shown in FIG. 14, in which the plates 26 an 26' of a twist stopper similar to that shown in FIG. 3 are for instance connected to each other by a. pair of dowels 62 which may be press fitted in bores in one of the plates and extend with a sliding fit in aligned bores of the other plate so that the two plates are movable substantially parallel to each other toward and away from each other. One of the plates, for instance the plate 26' may be 6 fixedly connected to a bracket 67 as indicated in FIG. 14. The plate 26 may be provided with a boss 63 projecting from one edge face thereof and the plate 26' may be provided with a corresponding boss 63. The boss 63 may be provided with a bore formed with a fine screw thread into which the correspondingly threaded portion of a screw 64 extends which passes through a non-threaded bore through the boss 63'. The latter boss may be provided on a side face thereof with a scale 65 cooperating with a mark 66 on the screw 64 so that by turning of the screw 64 the width of the opening 25 defined by opposite portions of the two plates may be changed to accommodate yarns of different diameters. The scale 65 may be provided with appropriate markings to facilitate adjustment of the twist stopper for yarns of specific diameter.

Obviously, the adjusting arrangement illustrated in FIG. 14 may be varied in many dilterent Ways, for instance the dowel 62 and the screw 64 could be rearranged in such a manner to facilitate the threading of the yarn between the plates from one side of the latter.

The ability of false twist means to crimp yarn is dependent on the elastic and plastic properties of yarn in the twisting zone, and these properties are temperature dependent. The t-wist stopper 21 (FIG. 1) may be situated upstream of the upstream end of the heating zone 13 and downstream of the nip-forming rolls 17 have hitherto assumed the role of twist stopper means, or at the upstream end of the heating zone 13, or (FIG. 2) actually within the limits of the heating zone 13, in particular, at the point therein where the yarn reaches the temperature, at which it is subsequently maintained for a time sufficient to set it. In the latter case all yarn in the twisting zone is at a substantially uniform temperature. The yarn contact zone may (FIG. 13) comprise a multi-track yarn contact heater 13; and there may be a plurality of yarn twist stoppers 21, one for each track of the heater located intermediate the upstream and downstream ends of the heater.

It will be understood that each of the elements described above, or two or more together, may also find a useful application in other types of spinning apparatus differing from the type described above.

While the invention has been illustrated and described as embodied in yarn spinning apparatus with twist stopper, it is not intended to be limited to the details shown, since various modification and structural changes may be made without departing in any way from the spirit of the present invention.

Without further analysis, the foregoing will so fully reveal the gist of the present invention that others can by applying current knowledge readily adapt it for various applications without omitting features that, from the standpoint of prior art, fairly constitute essential characteristics of the generic or specific aspects of this invention and, therefore, such adaptations should and are intended to be comprehended within the meaning and range of equivalence of the following claims.

What is claimed as new and desired to be secured by Letters Patent is:

1. A yarn processing apparatus comprising, in combination, means for advancing a yarn in one direction along a path; means located along said path and operable to twist the yarn advanced along said path; and twist stopper means located along said path upstream of said twisting means for preventing a twist produced in the yarn to pass through said twist stopper means, said twist stopper means having an opening defined at least in part by a pair of opposite wall portions located to opposite sides of said path and spaced apart a fixed distance such that a yarn passing therebetween is constrained against twisting by contact with said opposite wall portions so that whereas twist is produced by the twisting means in yarn in transit from the twist stopper means to the twisting means, no twist is produced by the twisting means in yarn in transit upstream of said twist stopper means.

2. An apparatus according to claim 1 in which the spacing of said opposed wall portions is such that, when yarn is passing between the opposed -wall portions, contact between the yarn and said opposed wall portions produces a temporary alteration in the cross-sectional shape of the yarn.

3. An apparatus according to claim 2 in which said two opposed wall portions are spaced apart by not less than twice the diameter of the individual filaments of the yarn, which, in operation, is to pass between said opposed wall portions.

4. An apparatus according to claim 1 in which said twist stopper means has, downstream of the said opposed wall portions further wall portions, which define a space tapering in a direction towards the space between said opposed wall portions and between which, in operation, yarn passes after passing between the said opposed wall portions.

5. An apparatus according to claim 3 in which said twist stopper means comprises two spaced walls at least one of which has a surface which has a convex curvature in a plane containing the path of movement of yarn between said two spaced walls; said opposed wall portions are constituted by portions of said two spaced walls where the spacing between the said two spaced walls is least; and the tapering space is defined by wall portions, of said two spaced walls, contiguous with said opposed wall portions.

6. An apparatus according to claim 5 in which the said two spaced walls are constituted by parallel rod-like members.

7. An apparatus according to claim 6 and including backing members supporting the rod-like members so as to prevent their bending or fracture.

8. An apparatus according to claim 3 in which said opposed wall portions are opposed wall portions of a channel.

9. An apparatus according to claim 3 in which said opposed wall portions are opposed wall portions of an aperture.

10. An apparatus according to claim 9 in which said aperture has a circular cross-section, diametrically opposed wall portions of said aperture constituting said 0pposed wall portions.

11. An apparatus according to claim 10 in which said aperture comprises the bore of a fine-bore tube such, for example, as is employed in the manufacture of hypodermic needles.

12. An apparatus according to claim 11 in which said tube has at least one belled end which defines a tapering space directed towards said aperture.

13. An apparatus according to claim 10 in which said aperture comprises a fine bore through a plate.

14. An apparatus according to claim 13 in which said aperture is one of a plurality of apertures of circuluar cross-section, said apertures having different diameters so as to accommodate the passage of yarns of different diameters.

15. An apparatus according to claim 3 in which said twist stopper means comprises two parts which are fitted together and each of which comprises one of said two opposed wall portions.

16. An apparatus according to claim 1 in which said opposed wall portions are constituted by circumferentially extending portions of two rotary members having parallel axes of rotation.

17. An apparatus according to claim 16 in which said rotary members comprise contacting rotary rolls; and said opposed wall portions are circumferentially extending portions of said rotary rolls. I

18. An apparatus according to claim 1 in which said opposed wall portions comprise a hard material having a low coefiicient of friction relatively to the yarn.

19. An apparatus according to claim 18 in which the hard material comprises synthetic sapphire.

20; An apparatus according to claim 1 in which said twisting means comprises: yarn false twist means; and a yarn heating zone located between said false twist means and said twist stopper means and adapted to heat set yarn in transit from said twist stopper to said false twist means.

21. An apparatus according to claim 20 wherein said yarn twist stopper means is located adjacent the downstream end of said heating zone; and said yarn advancing means comprising first nip-forming rolls downstream of said heating zone and operable to advance yarn to be false crimped, and second nip-forming rolls located downstream of said false twist means to advance yarn from said first nip-forming rolls through said twist stopper means, said heating zone and said false twist means, and to advance false twist crimped yarn issuing from said false twist means for a further processing.

22. A yarn twist stopper for use in a yarn processing apparatus including means operable to twist a yarn, said twist stopper comprising opposed wall portions which are spaced apart by a fixed distance, such that when yarn is forwarded between said opposed wall portions, contact between the yarn and said opposed wall portions alters the cross-sectional shape of the yarn for the interval during which the yarn contacts said opposed wall portions.

23. A yarn twist stopper according to claim 22 in which said two opposed wall portions are spaced apart by not less than twice the diameter of the individual filaments of yarn which, in operation, is to pass between said opposed wall portions.

24. A yarn twist stopper according to claim 22 which has further wall portions which define a space tapering in a direction towards the space between the said opposed wall portions and between which, in operation, yarn passes after passing between the said opposed wall portions.

25. A yarn twist stopper according to claim 24 which comprises two spaced walls at least one of which has a surface which has a convex curvature in a plane containing the path of movement of yarn between said two spaced walls; said opposed wall portions are constituted by portions of said two spaced walls where the spacing between said two spaced walls is least; and the tapering space is defined by wall portions of said two spaced walls, contiguous with said opposed wall portions.

26. A yarn twist stopper according to claim 25 in which said two spaced walls are constituted by two parallel rod-like members of a hard material, such as synthetic sapphire, which has a low coefiicient of friction relatively to the yarn.

27. A yarn twist stopper according to claim 26 and including backing members supporting said rod-like members against bending or fracture.

28. A yarn twist stopper according to claim 22 in which said opposed wall portions are opposed wall portions of a channel.

29. A yarn twist stopper according to claim 22 in which said opposed wall portions are opposed wall portions of an aperture.

30. A yarn twist stopper according to claim 29 in which said aperture has a circular cross-section, diametrically opposed wall portions of said aperture constituting said opposed wall portions.

31. A yarn twist stopper according to claim 30 in which said aperture comprises the bore of a fine-bore tube, such, for example, as is employed in the manufacture of hypodermic needles.

32. A yarn twist stopper according to claim 31 in which at least one end of said tube is belled out so as to define a tapering space directed towards the said aperture.

33. A yarn twist stopper according to claim 30 in which said aperture comprises a fine bore through a plate.

34. A yarn twist stopper according to claim 33 in which said aperture is one of a plurality of apertures, of circular cross section, through said plate, said apertures having dilferent diameters so as to accommodate the passage of yarns of different diameters.

35. A yarn twist stopper according to claim 23 which comprises two parts which are fitted together and each of which has one of said opposed wall portions.

36. A yarn twist stopper according to claim 35 which comprises fine adjustment means operatively connected to said two parts for displacing the latter relatively to one another so as to adjust the spacing between said opposed wall portions in accordance with the yarn which is to pass between said opposed wall portions.

37. A yarn twist stopper according to claim 36 in which said adjustment means is calibrated in terms of yarn which may pass between said opposed wall portions.

10 References Cited UNITED STATES PATENTS 2,788,634 4/1957 Crouzet 57106 2,952,964 9/1960 Gonsalves et a1. "57-34 3,153,891 10/1964 Kissler 57-34 3,330,104 7/1967 Dunwoody 57--106 FOREIGN PATENTS 657,960 3/1938' Germany.

STANLEY N. GILREATH, Primary Examiner.

WERNER H. SCHROEDER, Assistant Examiner. 

